One of our most popular natives, cabbage trees have bloomed spectacularly this summer. Gillian Vine reports.
Did you notice how profusely ti kouka (cabbage trees) flowered this season?
Moreover, in most places, they bloomed a tad earlier than usual and according to Ngai Tahu tradition, that forecast a long hot summer.
As much of Otago is enduring extremely low levels of soil moisture, the cabbage trees (Cordyline australis) obviously knew what to expect.
Captain James Cook is given credit for the common name of the tree, having apparently fed his crew on the boiled inner leaves in an effort to prevent scurvy.
The name cabbage tree has stuck, although ti kouka is more attractive.
Sometimes translated as footprints in the landscape, it refers to the Maori practice of planting C. australis as route markers as the trees can live for hundreds of years.
Ti kouka had other uses.
The taproots were harvested when the trees were in flower and roasted to produce a form of sugar; starch came from steamed trunks; while the leaves were used to make sandals, medicines and a strong fibre that was more resistant to sea water than flax rope.
Gardeners who have C. australis know about those strong leaves, as any left on the lawn before mowing get caught in the blades and cause problems.
If your patience runs out and you decide to cut down your cabbage tree, it may avenge itself: the trunk will show sprouts in no time at all with multiple Icabbages'' appearing.
Despite the minor nuisance of fallen leaves, cabbage trees are a familiar garden sight, especially now that there are so many cultivated forms with variegated stripes of pink, purple, lemon, cream and green.
Smaller varieties are suitable for containers, while taller ones like C. australis Purpurea and green-and-white Albertii are fine landscaping plants for bigger gardens.
Red Star, Midnight Star, Burgundy Star and Chocolate Mint are smaller (3m) C. australis varieties.
Other newer cabbage trees are hybrids using different native species, notably C. pumilio - a short, almost grass-like plant from the northern half of the North Island - and C. banksii, the forest cabbage tree.
The "Electric'' series, including Electric Star and Electric Pink, are highly coloured C. banksii hybrids.
Red Fountain, a C. pumilio x C. banksii cross is justly popular in the South for its narrow purple leaves. C. kaspar, from the Three Kings, is a parent of Green Goddess but unfortunately the species and its cultivars tend to be prone to root rot (phytophthora).
An easy-to-grow member of the same family as asparagus, C. australis is widely grown overseas for its somewhat tropical look.
In Torquay, Devon, where it is known as Torquay or Torbay palm, trees were planted during World War 1, as there was a rehabilitation centre in the town.
Apparently, the New Zealander whose idea it was to plant ti kouka wanted to remind the men of home.
In 2009, Torbay palms were removed from a flower bed near the harbour, causing howls of protest from councillors, shopkeepers and residents, so they still have their fans there, although with a good-sized plant costing about $170 in English nurseries, they may not be within every English gardener's budget.
Cabbage trees flower in November or December and provide nectar for tui and bellbirds as well as some lizards. The white fruit - sometimes mistaken for flowers - ripens from March to May and is also favoured by birds, including kereru.
Apart from C. kaspar and its hybrids, cabbage trees are usually disease-free but one pest hits C. australis.
This is the cabbage tree moth (Epiphryne verriculata), one of our larger native moths, with a wingspan of 40mm.
It is beige in colour, with attractive patterns of fine horizontal stripes that make it hard to spot on the tree trunk where it rests.
The caterpillars are green, a colour designed to camouflage.
Night feeders, they hit young leaves, resulting in holes and notches that look unsightly as the leaves develop.
Derris dust sprinkled into the centre of young plants is very effective but will also kill hoverfly larva, which feed on small caterpillars.
Left untreated, the problem resolves itself as nibbled leaves die and older trees are usually untouched, possibly because the moths cannot fly high enough to lay eggs in them.
As well as a range of colours and sizes for gardens large and small, cabbage trees have another plus: if you fancy taking over from the National Institute of Water and Atmospheric Research (Niwa) and do some weather forecasting, just add a ti kouka tree to your patch.
